Author(s)

Date Approved

Embargo Period

Document Type

Degree Name

Department

College

Henry M. Rowan College of Engineering

First Advisor

Newell, James

Subject(s)

Fibrous composites; Polyamide fibers; Polyphenyleneterephthalamide

Disciplines

Chemical Engineering

Abstract

The purpose of this exploratory investigation was to elucidate the structural mechanism accounting for the enhanced compressive properties of heat-treated Kevlar-29® fibers. A novel theory was set forth that hydrogen bond disruption and concurrent misorientation of crystallites may account for the observed augmentation of compressive properties. To examine the said theory, virgin Kevlar-29® fibers were characterized by Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) in an effort to determine if crosslinking and/or hydrogen bond disruption was responsible for the improved behavior in compression. Additionally, Kevlar-29® fibers that had been exposed to treatment temperatures of 400, 440, and 470 °C were profiled by Fourier-Transform Infrared Spectrophotometry (FTIR) to determine if crosslinking and/or hydrogen bond obfuscation had been promoted. The results indicate that both mechanistic changes are occurring within the Kevlar-29®, albeit in different regions of the rigid-rod polymer. In particular, heat-treatment of poly-p-phenylene terephthalamide results in crosslinking of its skin region and hydrogen bond disruption within the core realm.